A system for controlling the velocity of a motor vehicle is described, for example, in U.S. Pat. No. 5,014,200. This system maintains a velocity, which can be set by the operator, as long as there are no other vehicles driving in front of the controlled vehicle, and adjusts the vehicle velocity when another vehicle is detected ahead, in order to maintain a distance between the vehicles, which can also be programmed by the operator. An alarm distance is calculated as a function of the driver's reaction time. To enable the driver to set the distance between the vehicles, the vehicle operator can set the term for the driver reaction time. As described in U.S. Pat. No. 5,014,200, this should be done with a view to the driver's personal driving habits and with a view to certain weather, road, and traffic conditions. The disadvantage of this conventional system is that the driver must manually adjust the control response of the system to different situations. If the driver forgets a setting, or if an environmental condition changes very quickly, a dangerous situation, caused for example by unwanted acceleration of the controlled vehicle under the environmental condition, may occur.
German Patent Application No. 195 30 289 describes a sensor for determining visibility and road slickness which can compensate for driving too fast under poor visibility conditions and the use of an automatic distance-adjusting cruise control system for a kind of "blind flying." The purpose of this visibility sensor is to provide information about actual visibility, and it can also supply this information to the adaptive cruise control (ACC) system. However, the sensor can determine visibility only when this visibility is limited by fog or rain. The sensor cannot reliably determine that the motor vehicle driver is being blinded by the light of oncoming traffic.
German Patent Application No. 40 35 451 describes a method for protecting the vehicle driver from being blinded by the headlights of other vehicles by changing the luminance inside the vehicle, using an arrangement of optoelectronic components. However, this German Patent Application also does not provide for supplying information to a cruise control system in a motor vehicle when driver blinding is detected.